Frequency scanned waveguide antennas have a variety of applications, such as scanning a weather radar antenna pattern in elevation. Frequency scanned waveguide antennas include frequency scanned waveguide antenna feeds, typically traveling wave sinuous feeds, for feeding a signal to an array of radiating waveguides. Sinuous feeds having E-plane (Electric field plane, narrow plane) bends are most commonly implemented due to their commercial availability and their ability to easily achieve low VSWR (Voltage Standing Wave Ratio) levels. However, sinuous feeds having E-plane bends are not low profile. Consequently, frequency scanned waveguide antennas having sinuous feeds with E-plane bends are not ideal for low profile applications such as weather radar. Low profile frequency scanned antenna applications can be addressed using sinuous feeds with H-plane bends. However, a sinuous H-plane bend topology requires parallel waveguide coupling, which exhibits a highly unstable phase response when using standard slot couplers. Standard slot couplers, e.g. tilted slots, work very well for coupling between orthogonal waveguides, but they exhibit high sensitivity to mechanical tolerances when used with parallel waveguides, rendering them unusable in a low cost manufacturing environment.
Therefore, it may be desirable to have a system for electronically scanning a weather radar antenna pattern in elevation which addresses the above-referenced problems and limitations of the current solutions.